Portable handheld power tools are pervasive. Such tools include, but are not limited to, saws, routers, sanders, screwdrivers, and of course, drills. Portable handheld drills, particularly corded and cordless electric drills, are uniquely useful portable power tools; and the present invention is particularly directed to handheld portable drills and drivers. For the sake of convenience, the term “drill” will henceforth refer to drills and drivers.
Portable handheld power drills have many plusses. They're portable, usually variable speed and reversible, and have, in many cases, keyless chucks that can receive a wide range of bits and other tools. But almost as a consequence of being so easy to use and portable, they are not inherently good at drilling precise, repeatable holes at a particular orientation and/or depth relative to the work piece. In addition, they have storage and charging (for cordless models) challenges and don't accommodate a variety of attachments such as lights, stud finders, lasers, handles, etc.
The present invention is preferably, though not solely, applied to a powered (e.g., corded, cordless, electric, battery, pneumatic) handheld drill; and includes a “drill guide” that operatively engages the drill motor to adjustably and precisely guide and control the drill thus significantly reducing if not eliminating the imprecision normally associated with such a tool. Additional embodiments include means for solving the above-mentioned storage, charging and attachment problems normally associated with portable handheld drills.
The primary aspect of the present invention relates to a “drill guide” that helps guide a portable handheld drill so as to increase its precision and utility. Various types of drill guides have been tried, including what might be called alignment guides, bit guides, carriage guides (housing and chuck) and housing guides. (Most of these terms have been derived by Applicants to describe the various types of drill guides.) And while aspects of the present invention could be applied to virtually any kind of drill guide, the preferred embodiment relates to the “housing guide” type of drill guide. That said, for the sake of completeness and to put the present invention into context, the other kinds of drill guides will be briefly discussed.
As noted above, the prior art includes various drill guides and related techniques and devices for addressing the fundamental shortcoming of portable power drills. One type of drill guide doesn't guide the drill motor, but rather provides visual feedback to the operator, to help the operator know when he or she is properly positioning and manipulating the drill so as to drill the desired hole. Examples of such “alignment guides” include levels (i.e. bubbles), sight apertures (e.g., U.S. Pat. No. 5,052,112) and lasers (e.g., U.S. Pat. No. 6,375,395). While such alignment guides are helpful, they do not guarantee precise drilling.
Another type of “drill guide” literally contacts the bit, as opposed to the drill motor, in an attempt to achieve a square or perpendicular hole, for example. See U.S. Des. Pat. 264,930 and U.S. Pat. No. 4,253,784. “Bit guides” are simple and inexpensive, but not particularly adjustable or precise, because, at least in part, of the inherent problems associated with directly contacting the bit.
A third and more precise type of “drill guide” could be termed a “housing carriage guide” wherein a “carriage” clamps or otherwise attaches to the drill motor housing, and the carriage in turn slidably connects to a post or “mast” assembly of some type. See U.S. Des. Pat. 291,528; and U.S. Pat. Nos. 6,860,682 and 4,349,301. The advantage of such a system is that it can be very precise; the disadvantage is the cost, complexity and additional weight of the carriage (i.e. the part or assembly that is fixed to the housing and slides on the post(s) or mast(s)).
A fourth type of “drill guide” is a “chuck carriage guide.” See U.S. Pat. Nos. 5,797,708; 4,923,341; 4,836,720; and 4,391,558. In this type of drill guide, there is a slidable (again, on one or more posts or masts) carriage that itself carries an additional chuck, and this additional chuck connects to and is driven by the normal drill chuck. Such drill guides are complex and bulky, given the fact that they have an extra chuck.
A fifth type of drill guide, and the type that includes the most preferred embodiment of the present invention, is a “housing guide” drill guide. This category of drill guide typically includes a groove or slide system for conveniently interfacing one or more posts or masts with the drill motor housing. Examples of “housing guide” drill guides are disclosed in U.S. Pat. Nos. 5,361,504; 4,765,786; 4,729,698; and 6,386,802. Advantages of this type drill guide include precision and inherent simplicity, e.g., no need for an additional carriage or the like.
One of the significant limitations of prior art “housing guide” drill guides is their inability to drill a sufficiently wide variety of holes in a precise, repeatable way. For example, many housing guides include means for drilling perpendicular/square holes in flat materials such as plywood. And many include adjustable “stops” to allow the repeated drilling of a plurality of holes at a pre-set depth. And many include V-shaped means for accommodating cross-sectional drilling of round stock and other elongate work pieces. But prior art “housing guides” do not include practical means for accurately and repeatedly drilling a pre-set distance from the edge of a work piece. One guide, shown in U.S. Pat. No. 4,729,698, includes an adjustable edge guide, but the '698 edge guide is cumbersome due to use of a pair of sliding rods captured by tubular pieces and held in place by four set screws. To change the edge offset, the user has to loosen all four set screws, slide the rods in or out of the tubular pieces, and re-tighten the set screws.
And no prior art drill guides, of any type, provide or accommodate a useful array of attachments and storage options. For example, there's no convenient way to store the edge guide of the '698 patent when it's not in use; nor does the '698 edge guide provide additional functionality (that is, it is an edge guide and only an edge guide).
The present invention is an entire tool system for addressing the shortcomings of prior art drill guides, and for providing enhanced storage and accessory options as well.